A connector terminal that is fitted in so as to pass completely through the housing of an electrical connector is formed with a plurality of concavities in the outer circumference of a bar-shape member so as to prevent a pull-out of the connector terminal from the housing. Such concavities are formed by depressing the outer circumference of the conductive bar-shape member by a tapered punch. A portion between the adjoining concavities is to be engaged with the internal surface of the housing. Unexamined Japanese Patent Application Kokai Publication No. 2014-203627 discloses such a connector terminal.
The connector terminal disclosed in Unexamined Japanese Patent Application Kokai Publication No. 2014-203627 includes, as illustrated in FIGS. 20 and 21, an engage portion 2 and a correction portion 3. The engage portion 2 is to be in contact with, with pressure being applied, the internal wall surface of an unillustrated holding hole which has a rectangular cross-sectional shape and which is formed in the housing. The correction portion 3 is provided at the front side relative to the engage portion 2 in the axial direction (at −Y side). The correction portion 3 is utilized to align the lengthwise direction of a terminal portion 1 (the same direction as a Y-axis direction) with the lengthwise direction of the holding hole (the same direction as the Y-axis direction). The correction portion 3 has an X-cross-sectional shape that is to contact the internal surface of the holding hole across a certain length. Four protrusions 7 that form the X-cross-sectional shape extend in the Y-axis direction. The external edge of the protrusion 7 is in parallel with the external edge of the terminal portion 1. According to the connector terminal employing the above structure, when the correction portion 3 is press-fitted in the holding hole of the housing, the protrusion 7 slightly bites into the corner of the holding hole while being aligned with the corner of the holding hole in the rectangular cross-sectional shape. Hence, the direction of the connector terminal and the entering posture thereof are corrected.
The engage portion 2 in contact with the internal wall surface of the holding hole of the housing includes engagement pieces 4a, 4b divided in the Y-axis direction of the terminal portion 1. The engagement pieces 4a, 4b have respective uniform XZ cross-sections that are symmetrical when viewed from the fit-in direction. Respective side faces of the engagement pieces 4a, 4b at +X side and at −X side are formed with V-grooves 5a, 5b across the whole lengths of the engagement pieces 4a, 4b. 
According to the connector terminal disclosed in Unexamined Japanese Patent Application Kokai Publication No. 2014-203627, since the V-grooves 5a, 5b are formed in the side faces of the engagement pieces 4a, 4b at +X side and at −X side, the thickness of the engagement pieces 4a, 4b at the corner is quite thin. Hence, the amount of bit-in by the engagement pieces 4a, 4b to the housing is little. Accordingly, the holding force of the connector terminal relative to the housing is weak, and when excessive pull-out force is applied to the connector terminal, the connector terminal may be pulled out.
Conversely, according to a connector terminal illustrated in FIG. 22, a concavity 20 formed in the outer circumference of a bar-shape member B0 in a square bar shape is formed as a V-groove that has an angle q1 of 90 degrees. Hence, the thickness of an engage portion 310 becomes substantially uniform from the basal end to the front end. Accordingly, the sufficient amount of bite-in by the engage portion 310 to a housing can be ensured. Consequently, the holding force of the connector terminal relative to the housing can be improved.
However, in order to form such an engage portion 310, when the outer circumference of a bar-shape member to which plating is applied is depressed by a punch that has an angle of the front end which is 90 degrees, when the front end of the punch bites in the bar-shape member, the plating is likely to be peeled off. In addition, together with the advancement of the depression by the punch, the tapered punch deeply bites into the bar-shape member. This gradually peels off the plating while pushing and spreading the concavity 20. Therefore, the plating peeled pieces are accumulated on the punch.
Hence, when the punch is applied multiple times to produce the connector terminal, a large amount of plating peeled pieces may be accumulated on the inclined face of the punch, and a cleaning work to eliminate the accumulated plating from the punch is necessary in this case. When a cleaning work for the punch is carried out, the production of the connector terminal should be suspended.
The amount of plating peeled piece accumulated on the inclined face of the punch gradually increases from the front end of the punch toward the basal end thereof. Hence, the accumulated plating peeled pieces are formed in a shape like a thin and elongated string along the lengthwise direction of the connector terminal. In this case, the string-like plating peeled pieces may stride over the adjoining connector terminals, causing a short-circuit of the connector terminals.
When the concavities are formed by a punch that has an angle of the front end which is larger than 90 degrees, since such a punch depresses a plating so as to hold down the plating, a peeling of the plating can be suppressed. For example, by forming the concavities 20 formed as a V-groove that has an angle q2 of 120 degrees by a punch which has the angle of the front end that is 120 degrees, a peeling of the plating can be suppressed. In this case, however, the thickness of an engage portion 320 (engage portion 320 indicated by dashed lines in FIG. 22) gradually becomes thin from the basal end toward the front end. Accordingly, the holding force of the connector terminal relative to the housing may decrease.